He's doing something illegal but I think it's rational. The woman can do everything the man can, but the man won't take paternity in practice.

He can also convince a man wanting to leave with money or opportunities but he can't convince a woman giving birth.

It's kinda super skeevy, but I'm not seeing the inconsistency.

Men switch jobs at higher rates than women do, so it's easy to argue that the OP is taking more risks by hiring exclusively men.

And women at home doing childcare don't become inaccessible the way that men working for a competitor are. They're much more likely to answer if you ask them a question. In my personal experience anyways.

Haha, okay, I’m easy to convince because I really haven’t thought about the problem and I could never see myself needing to reason it out since it’s just illegal and therefore overridden by the objective to ensure my company doesn’t get sued into oblivion.